Battery control unit and battery system

Abstract

To provide a battery control unit and a battery system capable of suppressing a power supply stop during bypassing.SOLUTION: Switching parts 31a to 31c are provided respectively for batteries 21 to 21c connected in serial to each other and switch between a connection state in which the corresponding batteries 21a to 21c can be electrically discharged and a non-connection state in which the corresponding batteries 21a to 21c cannot be discharged. A capacitor 5 is connected in parallel with the batteries 21a to 21c.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery control unit and a battery system. [Background technology]

[0002] There is a battery system that is composed of multiple batteries connected in series. The deterioration of the multiple batteries varies due to, for example, variations during manufacturing or variations in the operating environment. For example, batteries close to a heat source deteriorate quickly, while batteries far from the heat source deteriorate slowly.

[0003] For this reason, during charging and discharging, the most deteriorated battery will be the first to reach the charge / discharge end voltage. In this case, even if other batteries have remaining capacity, charging and discharging must be stopped, and the battery capacity cannot be fully used. Therefore, a system has been proposed in which a battery that has reached the charge end voltage is bypassed and disconnected from the charging circuit, while continuing to charge batteries that have not yet reached the charge end voltage (Patent Document 1). Similarly, a battery system is conceivable that during discharging, bypasses a battery that has reached the discharge end voltage and disconnects it from the discharge circuit, while continuing to discharge batteries that have not yet reached the discharge end voltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-31249 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional battery system described above has a problem in that each time the battery is bypassed, the connection between the battery and the load is momentarily cut off, causing a momentary interruption in the supply of power to the load.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a battery control unit and a battery system that can suppress power supply interruption during bypass. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a battery control unit and a battery system according to the present invention are characterized by the following [1] to [3]. [1] a switching unit provided for each of the plurality of batteries connected in series to switch between a connection state in which the corresponding battery can be discharged and a non-connection state in which the corresponding battery cannot be discharged; a power storage device connected in parallel to the plurality of batteries, a first assembled battery consisting of a plurality of the batteries connected in series to each other, and a second assembled battery consisting of a plurality of the batteries connected in series to each other are connected in parallel; a switch provided in each of the first assembled battery and the second assembled battery for turning on and off a connection between the corresponding assembled battery and a load supplied with power from the assembled battery; Each time a switching from the connected state to the non-connected state occurs for any one of the batteries included in the first assembled battery and the second assembled battery based on the reaching of a discharge end voltage of a voltage across both ends of the battery, turning on the switch of the first assembled battery or the second assembled battery having a higher total voltage, which is a sum of voltages across both ends of the batteries in the connected state, and turning off the switch of the battery having a lower total voltage. It is a battery control unit. [2] A battery control unit according to [1], The battery is charged from a solar power generator and a charger. It is a battery control unit. [3] A plurality of batteries connected in series with each other; a switching unit provided for each of the plurality of batteries, the switching unit switching between a connected state that allows the corresponding battery to be discharged and a non-connected state that prevents the corresponding battery from being discharged; a power storage device connected in parallel to the plurality of batteries, a first assembled battery consisting of a plurality of the batteries connected in series to each other, and a second assembled battery consisting of a plurality of the batteries connected in series to each other are connected in parallel; a switch provided in each of the first assembled battery and the second assembled battery for turning on and off a connection between the corresponding assembled battery and a load supplied with power from the assembled battery; Each time a switching from the connected state to the non-connected state occurs for any one of the batteries included in the first assembled battery and the second assembled battery based on the reaching of a discharge end voltage of a voltage across both ends of the battery, turning on the switch of the first assembled battery or the second assembled battery having a higher total voltage, which is a sum of voltages across both ends of the batteries in the connected state, and turning off the switch of the battery having a lower total voltage. It is a battery system.

[0008] The above [1] and [ 3 In the battery control unit and battery system having the above configuration, the power storage device is connected in parallel to the multiple batteries. As a result, when the switching unit switches the battery from a connected state to a disconnected state, the connection between the battery and the load is momentarily cut off, but the power storage device can continue to supply power to the load while the connection is cut off.

[0009] Furthermore, the above [1] and [3] Configuration of the battery control unit and battery system According to the document, when a switch is turned on to switch a battery pack connected to a load, the connection between the battery and the load is momentarily cut off, but power supply can continue from the power storage device while the connection is cut off.

[0010] the above[ 2 In a battery control unit having the above configuration, when the switching unit switches the battery from a connected state to a disconnected state while the battery is being charged from the solar power generator, the connection between the battery and the solar power generator is momentarily cut off. At this time, the power storage device absorbs the charging current from the solar power generator, so high voltage from the solar power generator is not applied to the charger, and it is possible to prevent the charger from breaking down. Effect of the Invention

[0011] According to the present invention, it is possible to provide a battery control unit and a battery system that can suppress interruption of power supply during bypass.

[0012] The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following description of the embodiment of the present invention (hereinafter, referred to as "embodiment") with reference to the accompanying drawings. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a circuit diagram showing a battery system in a first embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart illustrating a discharge process procedure of the control unit shown in FIG. [Diagram 3] FIG. 3 is a circuit diagram showing a battery system according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart showing a discharge process procedure of the control unit shown in FIG. [Diagram 5] FIG. 5 is a circuit diagram showing a battery system according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0015] (First embodiment) A battery system 1 shown in FIG. 1 is a device that supplies power by reusing, for example, deteriorated batteries.

[0016] As shown in the figure, the battery system 1 includes a plurality of batteries 21a-21c and a battery control unit 3. In this embodiment, for simplicity, an example in which three batteries 21a-21c are connected in series will be described, but the present invention is not limited to this. The number of batteries 21a-21c may be two or four or more as long as it is more than one. Each of the plurality of batteries 21a-21c is a rechargeable storage battery and may be composed of one cell or multiple cells.

[0017] The battery control unit 3 includes a plurality of switching units 31a-31c, a plurality of voltage measuring units 41a-41c, a capacitor 5 (power storage device), and a control unit 6. The plurality of switching units 31a-31c are provided corresponding to the plurality of batteries 21a-21c, respectively. The plurality of switching units 31a-31c have the same configuration.

[0018] The switching units 31a to 31c switch between a connection state in which the corresponding batteries 21a to 21c can be connected (discharged) to a charger or load 7 (not shown) and a non-connection state in which the corresponding batteries 21a to 21c cannot be connected (discharged) to a charger or load 7 (not shown). That is, the batteries 21a to 21c in the connection state are electrically connected between a pair of terminals T1, T2, and the batteries 21a to 21c in the non-connection state are electrically disconnected from the pair of terminals T1, T2. Therefore, when the terminals T1, T2 are connected to a charger or load 7 (not shown), the batteries 21a to 21c in the connection state are connected to the charger or load 7, and the batteries 21a to 21c in the non-connection state are disconnected from the charger or load 7.

[0019] The switching unit 31a is composed of a first switch SW11a connected in series to the battery 21a, and a second switch SW12a connected in parallel to the battery 21a and the first switch SW11a. One end T11 of the first switch SW11a is connected to one pole (e.g., positive pole) of the battery 21a. One end T21 of the second switch SW12a is connected to the other pole (e.g., negative pole) of the battery 21a, and the other end T22 is connected to the other end T12 of the first switch SW11a. The switching units 31b and 31c can be described by replacing "a" in the above description of the switching unit 31a with "b" to "c", respectively, and detailed description will be omitted.

[0020] The other end T12 of the first switch SW11b is connected to the negative electrode of the battery 21a, and the other end T12 of the first switch SW11c is connected to the negative electrode of the battery 21b. That is, the first switches SW11b and SW11c are connected between adjacent batteries 21a and 21b, and between adjacent batteries 21b and 21c, respectively.

[0021] According to the above configuration, when the second switches SW12a-SW12c are turned off and the first switches SW11a-SW11c are turned on, the corresponding batteries 21a-21c are in a connected state. When the first switches SW11a-SW11c are turned off, the corresponding batteries 21a-21c are in a disconnected state. At this time, when the second switches SW12a-SW12c are turned on, a bypass path is formed, and only the batteries 21a-21c in a connected state are connected between the terminals T1 and T2.

[0022] The voltage measuring units 41a to 41c are provided corresponding to the batteries 21a to 21c, respectively. The voltage measuring units 41a to 41c measure the voltages across the corresponding batteries 21a to 21c, and output the measurement results to the control unit 6, which will be described later.

[0023] The capacitor 5 is connected in parallel to the plurality of batteries 21a to 21c. As a result, when the connection between the batteries 21a to 21c and the load 7 is cut, power is supplied from the capacitor 5 to the load 7, so that the power supply to the load 7 can be continued.

[0024] The control unit 6 is composed of a known CPU, ROM, and RAM, and is responsible for controlling the entire battery system 1. The control unit 6 controls the switching units 31a to 31c based on the voltages across each of the batteries 21a to 21c.

[0025] Next, the operation of the battery system 1 configured as described above during discharging will be described with reference to Fig. 2. When the control unit 6 receives a discharge mode instruction, it executes the discharge process shown in Fig. 2. First, the control unit 6 turns off all the first switches SW11a-SW11c and the second switches SW12a-SW12c (step S1). Then, the control unit 6 turns on all the first switches SW11a-SW11c (step S2). This puts the batteries 21a-21c in a connected state, and the batteries 21a-21c in a dischargeable state. Then, the control unit 6 starts discharging the batteries 21a-21c (step S3).

[0026] Thereafter, the control unit 6 measures the voltages across the batteries 21a-21c using the voltage measuring units 41a-41c, and judges whether the voltages across the batteries 21a-21c have reached the discharge end voltage (step S4). If any of the batteries 21a-21c have reached the discharge end voltage (Y in step S4), the control unit 6 judges whether all of the batteries 21a-21c have reached the discharge end voltage (step S5). If all of the batteries 21a-21c have not reached the discharge end voltage (N in step S5), the control unit 6 turns off the first switches SW11a-SW11c corresponding to the batteries 21a-21c that have reached the discharge end voltage, and then turns on the second switches SW12a-SW12c (step S6). As a result, the batteries 21a-21c that have reached the discharge end voltage are switched from a connected state to a non-connected state, and the batteries 21a-21c that have reached the discharge end voltage are bypassed.

[0027] In step S6, the connection between the batteries 21a to 21c and the load 7 is momentarily cut off from the time the first switches SW11a to SW11c are turned off until the second switches SW12a to SW12c are turned on, but while the connection is cut off, power supply to the load 7 can be continued by the capacitor 5.

[0028] On the other hand, if all the batteries 21a-21c have reached the discharge end voltage (Y in step S5), the control unit 6 stops discharging (step S7) and turns off all the first switches SW11a-SW11c and the second switches SW12a-SW12c (step S8). After that, the control unit 6 turns on all the first switches SW11a-SW11c (step S9) and then ends the process.

[0029] According to the embodiment described above, the capacitor 5 is connected in parallel to the multiple batteries 21a-21c. As a result, when the switching units 31a-31c switch the batteries 21a-21c from a connected state to a disconnected state, the connection between the batteries 21a-21c and the load 7 is momentarily cut off, but the capacitor 5 can continue to supply power to the load 7 while the connection is cut off.

[0030] Second embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 3. In the figure, parts equivalent to those of the battery system 1 shown in Fig. 1 already described in the first embodiment above are given the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, the battery system 1 further includes a battery pack BP1 and a battery pack BP2, which are connected in parallel with each other, and switches SW1 and SW2. Each of the battery packs BP1 and BP2 includes batteries 21a to 21c.

[0031] In the present embodiment, for the sake of simplicity, the battery system 1 will be described having two battery packs BP1 and BP2, but the present invention is not limited to this. The number of battery packs may be three or more.

[0032] The switches SW1, SW2 are provided for each of the assembled batteries BP1, BP2, and turn on and off the connection between the corresponding assembled batteries BP1, BP2 and the load 7.

[0033] Next, the operation of the battery system 1 configured as described above during discharging will be described with reference to Fig. 4. In Fig. 4, steps equivalent to those in Fig. 2 described in the first embodiment above are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0034] When the control unit 6 receives the discharge mode command, it executes the discharge process shown in Fig. 4. First, the control unit 6 executes steps S1 and S2 as in the first embodiment. After that, the control unit 6 turns on the switches SW1 and SW2 of the assembled batteries BP1 and BP2 that have a higher total voltage, and turns off the switches SW1 and SW2 of the assembled batteries BP1 and BP2 that have a lower total voltage (step S10). The total voltage is the sum of the voltages across both ends of the batteries 21a to 21c that are connected among the assembled batteries BP1 and BP2.

[0035] Thereafter, the control unit 6 executes steps S3 to S9 in the same manner as in the first embodiment. After executing step S6, the control unit 6 turns off the switches SW1 and SW2 of the assembled batteries BP1 and BP2 that have a lower total voltage, turns on the switches SW1 and SW2 of the assembled batteries BP1 and BP2 that have a higher total voltage (step S11), and then returns to step S4. When the switches SW1 and SW2 that are turned on in step S11 are switched from switch SW1 to switch SW2, for example, the control unit 6 turns off switch SW1 and then turns on switch SW2.

[0036] Therefore, the connection between the batteries 21a to 21c and the load 7 is momentarily cut off from the time when the switch SW1 is turned off until the switch SW2 is turned on. However, the capacitor 5 can continue to supply power to the load 7 while the connection is cut off.

[0037] In the above-described first and second embodiments, discharging has been described, but similarly, during charging, charging of the batteries 21a to 21c can be continued by the capacitor 5 while the batteries 21a to 21c are disconnected from a charger (not shown).

[0038] Third embodiment Next, a third embodiment of the present invention will be described with reference to Fig. 5. In this figure, parts equivalent to the battery control unit 3 shown in Fig. 1 already described in the first embodiment above are given the same reference numerals, and detailed description thereof will be omitted. The battery system 1 in the third embodiment is premised on being used in a place equipped with a solar power generator 8, such as a home.

[0039] In the third embodiment, the batteries 21a to 21c are charged by a solar power generator 8 and a charger 9. The solar power generator 8 converts sunlight into electricity to charge the batteries 21a to 21c. The charger 9 obtains power from a household or other AC power source to charge the batteries 21a to 21c.

[0040] According to the battery system 1 described above, when the switching units 31a-31c switch the batteries 21a-21c from a connected state to a disconnected state while the batteries 21a-21c are being charged by the solar generator 8, the connection between the batteries 21a-21c and the solar generator 8 is momentarily cut off. At this time, a malfunction occurs in the control of the solar generator 8, and the output voltage may become high. However, because the capacitor 5 absorbs the charging current from the solar generator 8, a high voltage from the solar generator 8 is not applied to the charger 9, and breakdown of the charger 9 can be prevented.

[0041] According to the first to third embodiments described above, the capacitor 5 is used as the power storage device, but the present invention is not limited to this. The power storage device may be composed of a battery, a capacitor, or the like.

[0042] Here, the features of the embodiments of the battery control unit and the battery system according to the present invention described above will be briefly summarized and listed in the following [1] to [4]. [1] switching units (31a to 31c) provided for each of a plurality of batteries (21a to 21c) connected in series with each other, for switching between a connection state in which the corresponding battery (21a to 21c) can be discharged and a non-connection state in which the corresponding battery (21a to 21c) cannot be discharged; and a power storage device (5) connected in parallel to the plurality of batteries (21a to 21c). Battery control unit (3). [2] A battery control unit (3) according to [1], a plurality of assembled batteries (BP1, BP2) each including a plurality of the batteries (21a to 21c) are connected in parallel; and a switch (SW1, SW2) provided for each of the plurality of assembled batteries (BP1, BP2) for turning on and off a connection between the corresponding assembled battery (BP1, BP2) and a load (7) to which power is supplied from the assembled battery (BP1, BP2). Battery control unit (3). [3] A battery control unit (3) according to [1] or [2], The batteries (21a to 21c) are charged by a solar power generator (8) and a charger (9). Battery control unit (3). [4] A plurality of batteries (21a to 21c) connected in series with each other; switching units (31a to 31c) provided for each of the plurality of batteries (21a to 21c), for switching between a connected state in which the corresponding battery (21a to 21c) can be discharged and a non-connected state in which the corresponding battery (21a to 21c) cannot be discharged; and a power storage device (5) connected in parallel to the plurality of batteries (21a to 21c). Battery system (1). [Explanation of symbols]

[0043] 1 Battery System 3 Battery Control Unit 5. Capacitor (electricity storage device) 7. Load 21a~21c battery 31a~31c Switching section BP1, BP2 assembled battery SW1, SW2 switches

Claims

1. a switching unit provided for each of the plurality of batteries connected in series to switch between a connection state in which the corresponding battery can be discharged and a non-connection state in which the corresponding battery cannot be discharged; a power storage device connected in parallel to the plurality of batteries, a first assembled battery consisting of a plurality of the batteries connected in series to each other, and a second assembled battery consisting of a plurality of the batteries connected in series to each other are connected in parallel; a switch provided in each of the first assembled battery and the second assembled battery for turning on and off a connection between the corresponding assembled battery and a load supplied with power from the assembled battery; turning on the switch of one of the first assembled battery and the second assembled battery, which has a higher total voltage, which is a sum of the voltages of the batteries at both ends of the batteries in the connected state, and turning off the switch of the one of the first assembled battery and the second assembled battery, which has a lower total voltage, each time switching from the connected state to the non-connected state occurs based on the voltage at both ends reaching a discharge end voltage; Battery control unit.

2. 2. The battery control unit according to claim 1, The battery is charged from a solar power generator and a charger. Battery control unit.

3. A plurality of batteries connected in series with each other; a switching unit provided for each of the plurality of batteries, the switching unit switching between a connected state that allows the corresponding battery to be discharged and a non-connected state that prevents the corresponding battery from being discharged; a power storage device connected in parallel to the plurality of batteries, a first assembled battery consisting of a plurality of the batteries connected in series to each other, and a second assembled battery consisting of a plurality of the batteries connected in series to each other are connected in parallel; a switch provided in each of the first assembled battery and the second assembled battery for turning on and off a connection between the corresponding assembled battery and a load supplied with power from the assembled battery; turning on the switch of one of the first assembled battery and the second assembled battery, which has a higher total voltage, which is a sum of the voltages of the batteries at both ends of the batteries in the connected state, and turning off the switch of the one of the first assembled battery and the second assembled battery, which has a lower total voltage, each time switching from the connected state to the non-connected state occurs based on the voltage at both ends reaching a discharge end voltage; Battery system.

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